3,390 research outputs found

    Identifying Finite-Time Coherent Sets from Limited Quantities of Lagrangian Data

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    A data-driven procedure for identifying the dominant transport barriers in a time-varying flow from limited quantities of Lagrangian data is presented. Our approach partitions state space into pairs of coherent sets, which are sets of initial conditions chosen to minimize the number of trajectories that "leak" from one set to the other under the influence of a stochastic flow field during a pre-specified interval in time. In practice, this partition is computed by posing an optimization problem, which once solved, yields a pair of functions whose signs determine set membership. From prior experience with synthetic, "data rich" test problems and conceptually related methods based on approximations of the Perron-Frobenius operator, we observe that the functions of interest typically appear to be smooth. As a result, given a fixed amount of data our approach, which can use sets of globally supported basis functions, has the potential to more accurately approximate the desired functions than other functions tailored to use compactly supported indicator functions. This difference enables our approach to produce effective approximations of pairs of coherent sets in problems with relatively limited quantities of Lagrangian data, which is usually the case with real geophysical data. We apply this method to three examples of increasing complexity: the first is the double gyre, the second is the Bickley Jet, and the third is data from numerically simulated drifters in the Sulu Sea.Comment: 14 pages, 7 figure

    On the α\alpha-decay of deformed actinide nuclei

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    α\alpha-decay through a deformed potential barrier produces significant mixing of angular momenta when mapped from the nuclear interior to the outside. Using experimental branching ratios and either semi-classical or coupled-channels transmission matrices, we have found that there is a set of internal amplitudes which are essentially constant for all even--even actinide nuclei. These same amplitudes also give good results for the known anisotropic α\alpha-particle emission of the favored decays of odd nuclei in the same mass region. PACS numbers: 23.60.+e, 24.10.Eq, 27.90.+bComment: 5 pages, latex (revtex style), 2 embedded postscript figures uuencoded gz-compressed .tar file To appear in Physical Review Letter

    Future eDestination Marketing: Perspective of an Australian Tourism Stakeholder Network.

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    Tourism destinations are difficult to manage because of the complex relationships of their diverse public and private stakeholders. At the same time, strategic marketing efforts are important for destinations to foster positive consequences of tourism, particularly given the range of opportunities and challenges created by the emergence of social media that destinations can use advantageously. This article aims to explore future eDestination marketing from Australian tourism stakeholder network perspectives. Workshops were convened in July 2012 in Melbourne, Australia, for select stakeholders invited to contribute to the futures national tourism technology strategy. They presented a stakeholder network approach to futures strategy development that aims to contribute to that used in recent national tourism plans and strategies for Australia developed by the government. Building on theories of stakeholder networks and futures, the article demonstrates the value of a futures stakeholder network method compared to traditional government approaches by critically analyzing outcomes of both

    Molecular cytogenetic characterization of breakpoints in 19 patients with hematologic malignancies and 12p unbalanced translocations

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    Structural rearrangements of the short arm of chromosome 12 are frequent cytogenetic findings in various hematologic malignancies. The ETV6 gene is the most common target for rearrangements in 12p13. Fluorescence in situ hybridization (FISH) investigations have shown that translocations of 12p other than t(12;21) are frequently accompanied by small interstitial deletions that include ETV6. Unbalanced translocations involving ETV6 have rarely been described, and breakpoints outside ETV6 appear to be strongly associated with complex karyotypes. We studied bone marrow samples from 19 patients known to have 12p unbalanced translocations and complex karyotypes, using FISH and spectral karyotyping. FISH analysis confirmed the hemizygous deletion of the ETV6 and CDKN1B genes in 74% of cases. We found four cases with interstitial deletions. In these four cases and in two others (6/19, 31.5%), the fusion with the partner chromosome was in the subtelomeric region of 12p13.3, confirming that there is a recurrent breakpoint in this region

    An exploratory study looking at the relationship marketing techniques used in the music festival industry

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    There are current issues and trends in the music festival market, which may affect the success of an event, and market saturation is at the forefront of these issues. Previous literature, maintaining the need for a marketing approach to festivals, identifi es the need for maintaining strong stakeholder relationships in order to succeed in a business environment; attention has been focused to the theory of relationship marketing (RM) because of the recognition that this practice is complementary to the marketing of festivals. The very nature of the music festival as an annual, usually, 4-day event means that effective marketing is needed to keep connections with the consumer throughout the year. This article focuses on the RM techniques utilised within the music festival industry from the viewpoint of the festival organiser in an attempt to establish how festival organisations value and monitor organisational relationships. This article explores the extent to which these relationships are valued and managed; furthermore, the variations between these intricate relationships are considered by focusing on those held with the organisation ’ s consumers and sponsors, the results of which have provided the ability to establish the importance and relevance of RM to the industry and further identify the marketing communication methods employed to establish and maintain such relationships. In-depth, convergent interviews have been conducted with a segment of music festival organisers from a range of events. The results have been integrated with the study of current literature to best exemplify these issues. It has been established that RM has a strong role in today ’ s commercial and independent music festival industry; technological advances are enabling the organiser to support online relationships further and increase consumer loyalty. There is a need to expand the research further because of the complexity of organisational relationships and the varying categories of festivals

    Identification of new translocations involving ETV6 in hematologic malignancies by fluorescence in situ hybridization and spectral karyotyping

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    TEL/ETV6 is the first transcription factor identified that is specifically required for hematopoiesis within the bone marrow. This gene has been found to have multiple fusion partners; 35 different chromosome bands have been involved in ETV6 translocations, of which 13 have been cloned. To identify additional ETV6 partner genes and to characterize the chromosomal abnormalities more fully, we studied bone marrow samples from patients known to have rearrangements of 12p, using fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY). FISH analysis was done with 14 probes located on 12p12.1 to 12p13.3. Nine ETV6 rearrangements were identified using FISH. The aberrations include t(1;12)(p36;p13), t(4;12)(q12;p13) (two patients), t(4;12)(q22;p13), t(6;12)(p21;p13), der(6)t(6;21)(q15;q?)t(12;21)(p13;q22), t(6;12)(q25;p13), inv(12)(p13q24), and t(2;2;5;12;17)(p25;q23;q31;p13;q12). Six new ETV6 partner bands were identified: 1p36, 4q22, 6p21, 6q25, 12q24, and 17q12. Our present data as well previous data from us and from other researchers suggest that ETV6 is involved in 41 translocations. The breakpoints in ETV6 were upstream from the exons coding for the HLH (helix-loop-helix) domain in six cases. Although cytogenetic analysis identified 12p abnormalities in all cases, FISH and SKY detected new and unexpected chromosomal rearrangements in many of them. Thus, complete characterization of the samples was achieved by using all three techniques in combination

    Building a Spiking Neural Network Model of the Basal Ganglia on SpiNNaker

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    We present a biologically-inspired and scalable model of the Basal Ganglia (BG) simulated on the SpiNNaker machine, a biologically-inspired low-power hardware platform allowing parallel, asynchronous computing. Our BG model consists of six cell populations, where the neuro-computational unit is a conductance-based Izhikevich spiking neuron; the number of neurons in each population is proportional to that reported in anatomical literature. This model is treated as a single-channel of action-selection in the BG, and is scaled-up to three channels with lateral cross-channel connections. When tested with two competing inputs, this three-channel model demonstrates action-selection behaviour. The SpiNNaker-based model is mapped exactly on to SpineML running on a conventional computer; both model responses show functional and qualitative similarity, thus validating the usability of SpiNNaker for simulating biologically-plausible networks. Furthermore, the SpiNNaker-based model simulates in real time for time-steps 1 ms; power dissipated during model execution is & #x2248;1.8 W

    Neutrino conversions in random magnetic fields and ν~e\tilde{\nu}_e from the Sun

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    The magnetic field in the convective zone of the Sun has a random small-scale component with the r.m.s. value substantially exceeding the strength of a regular large-scale field. For two Majorana neutrino flavors ×\times two helicities in the presence of a neutrino transition magnetic moment and nonzero neutrino mixing we analyze the displacement of the allowed (Δm2sin22θ\Delta m^2- \sin^22\theta)-parameter region reconciled for the SuperKamiokande(SK) and radiochemical (GALLEX, SAGE, Homestake) experiments in dependence on the r.m.s. magnetic field value bb, or more precisely, on a value μb\mu b assuming the transition magnetic moment μ=1011μB\mu = 10^{-11}\mu_B. In contrast to RSFP in regular magnetic fields we find an effective production of electron antineutrinos in the Sun even for small neutrino mixing through cascade conversions νeLνμLν~eR\nu_{eL}\to \nu_{\mu L}\to \tilde{\nu}_{eR}, νeLνμRν~eR\nu_{eL}\to \nu_{\mu R}\to \tilde{\nu}_{eR} in a random magnetic field that would be a signature of the Majorana nature of neutrino if ν~eR\tilde{\nu}_{eR} will be registered. Basing on the present SK bound on electron antineutrinos we have also found an excluded area in the same Δm2, sin22θ\Delta m^2,~\sin^22\theta-plane and revealed a strong sensitivity to the random magnetic field correlation length L0L_0.Comment: LaTex 36 pages including 14 PostScript figure

    Global Examination of the 12^{12}C+12^{12}C Reaction Data at Low and Intermediate Energies

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    We examine the 12^{12}C+12^{12}C elastic scattering over a wide energy range from 32.0 to 70.7 MeV in the laboratory system within the framework of the Optical model and the Coupled-Channels formalism. The 12^{12}C+12^{12}C system has been extensively studied within and over this energy range in the past. These efforts have been futile in determining the shape of the nuclear potential in the low energy region and in describing the individual angular distributions, single-angle 500^{0} to 900^{0} excitation functions and reaction cross-section data simultaneously. In order to address these problems systematically, we propose a potential that belongs to a family other than the one used to describe higher energy experimental data and show that it is possible to use it over this wide energy range. This potential also predicts the resonances at correct energies with reasonable widths.Comment: 30 pages with 13 eps figues and 3 tables, LaTeX-Revtex
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